Questions : is Chang’e 2 orbiter still in L2 ? I believe it’s the only one active there. Does it have any chance to take a picture of Webb ?

https://en.wikipedia.org/wiki/List_of_objec...range_points#L2

With regards to Chang'e2 ... I don't know. But if we hear, we should perhaps update the wiki article.

Yes that's part of it with the other considerations explained here:

https://blogs.nasa.gov/webb/2022/01/06/why-...oyment-cameras/

By the way, the first mirror wing deployment is in progress! There is a plan for live NASA TV coverage Jan 8 around 1400 UTC for the second wing.

Amateur telescopes will be able to image JWST (as a dot), given ephemeris and depending upon the reflective properties of the exposed sunshield. In fact, an amateur already did so while it was about 1/6 of the way to L2, and longer exposures will enable this to occur during its main mission. Of course, larger professional telescopes including HST will be able to image it.

But the sunshield will be the only part in sunlight, by design. We are never going to see pictures of it deployed looking elegant.

Good evening,

Excerpts from Wikipedia:

"According to Ouyang Ziyuan at the 16th conference of the Chinese Academy of Sciences, Chang'e 2 left Lagrange Point L2 on 15 April 2012 to fly over asteroid (4179) Toutatis."

"The probe is then placed on a flight path of the asteroid (4179) Toutatis15. The meeting took place on 13 December at 8:30 UTC at a relative speed of 10.73 km/s. Chang'e 2 passes a distance of 3.2 km from the asteroid and manages to take a dozen images of the asteroid with a maximum resolution of 10 meters per pixel."

"Since 2012, Chang'e 2 has left Earth-Moon space. In 2016, Chang'e 2 has reached a distance of 200 million km from Earth. The probe is used to verify the Chinese network tracking capabilities for far space. It could return to the terrestrial environment around 2029."

It's worth adding - the Lagrange points are not.....'points'. The spacecraft at L1, for example....there can be >500,00km between them, as they halo-orbit they way around.

For example, right now it's 468,000km between SOHO and DSCOVR, and 694,000km between DSCOVR and WIND, and 482,00km between WIND and SOHO

Even for something as powerful as HiRISE JWST would be a fraction of a pixel at those distances.

Thanks Doug, I knew it was a halo but didn’t knew it was that large

The left wing of primary mirror segments has been successfully deployed. Right wing deployment should begin next. There's no single moment when we will suddenly say that the risks of a successful JWST mission are all behind us, but things are definitely looking good now.

The telescope is now fully deployed, though latching activities continue.

Congratulations to the team!

NASA Twitter

This is a slowly-unfolding victory taking place. There are still many, many fine-tunings to be made with the actuators that will reorient each mirror segment to fine precision, and that step is crucially important to attaining proper focus. With memories of HST's focus problems, I don't want to count JWST's deployment as complete before this is done, but it certainly seems like the biggest points of failure – certainly by far the largest number of them – have been put behind the mission.

Not really worried about optics or focusing. Each primary segment has 7 degrees of freedom. I'm sure there's enough range to compensate for all sorts of scenarios. Hubble had nowhere near this level of control for focusing. JWST's testing was more integrated too.

Now.. Will the already 10+ years old electronics hold up? Computers/semiconductors, detectors, capacitors..

Chang'e2 is at the Earth-Moon L2 point. The JWST is going to be at the Earth-Sun L2 point. These are completely different locations.

CE-2 is in solar orbit after flying by Toutatis.
CE-5T1 is reportedly at the Earth-Moon L2, like the CE-4 relay satellite
The status of return module of CE-5 is not clear. After spending some time at one of the Earth-Sun Lagrangian points it is now back in lunar orbit or in a distant Earth orbit

Edit: CE-5 has just been recovered by radio-amateurs in lunar orbit https://twitter.com/coastal8049/status/1479619134681800704

For a commemorative photo, why not use Hubble or Keck.

Heidi Hammel addressed this at today's excellent JWST news conference and Q&A. She indicated that ground based images (already being taken by the amateur community for example) would be more likely than using Hubble. This question at 1:08:40 in the video.

https://www.c-span.org/video/?517137-1/jame...iefing&live

She then pivoted the question to joint science between Hubble and JWST. Also a good summary of solar system observations by JWST.